A mechanical switching device, such as a contactor, a relay, a contact breaker, etcetera, is a remotely operated electric switch used for establishing and disestablishing electric connection between the gap that separates the conductor members of the pair of conductor members from each other. In case the switching device is used for three-phase current, the switching device comprises three pairs of conductor members. The switch member comprises a moveable part that is displaced towards or away from the conductor members so that electric connection is established and disestablished between the conductor ends of the pair of conductor members.
Switching devices comprise many components, such as base member, conductor members, middle member and switch member, which are assembled together. This is done by means of an attachment arrangement comprising a large number of screw joints. Each conductor member needs to be attached to the base member in a certain position so that an appropriate gap between the conductor ends of the pair of conductor members is formed. Furthermore, the middle member needs to be attached to the base member and the switch member needs to be attached to the middle member.
In order to attach each conductor member to the base member, a switching device requires one screw joint per conductor member. Thus, a switching devices with three pairs of conductor members requires 2×3 screw joints for attaching the conductor members to the base member, at least 4 screw joints for the joining the base member and the middle member and at least 4 screw joints for attaching the switch member to the middle member.
A problem with manufacturing switching devices is that the assembly of the components is time consuming due to the large number of screw joints. Moreover, switching devices need to be disassembled for maintenance and replacement of components after certain period of operation.
US2007/0042624 presents a multi-phase switch gear device comprising pairs of conductor rails each having a bore, and two insert combs with protrusions entering the bore of each conductor rail. A problem with the disclosed switch gear device is that two insert combs are needed to attach the pair of conductor rails. The attachment of the pair of conductor rails thus requires two separate assembling steps during assemble of the device. Furthermore, the device requires a middle member that covers the conductor rails from the surrounding environment around the device. Such middle member is needed in order to assure that no foreign objects get in contact with the conductor rails, such as electrical conductive or semi-conductive elements.